Abstract: A flow control valve in which the hydraulic pressure difference exerted on a spool valve is controlled by regulating the degree of throttling of a variable orifice and the oil which is discharged from an oil pump is partly returned to the suction side of the oil pump in response to the degree of actuation of the spool valve according to the above hydraulic pressure difference, thereby controlling the quantity of oil that is fed to hydraulic devices. The flow passage to communicate the oil pump with the hydraulic devices includes a flow passage which permits the hydraulic oil to pass through a hole in which the spool valve is fitted, and a variable orifice is composed of an opening of the flow passage into the hole and a small diameter portion formed on the spool valve. The throttling of the variable orifice is attained by covering the opening with a predetermined clearance by the above small diameter portion.